On 11/28/2011 12:42 PM, Hans Verkuil wrote: > On Friday 25 November 2011 16:39:32 Sylwester Nawrocki wrote: >> On Exynos SoCs the FIMC IP allows to configure globally the alpha >> component of all pixels for V4L2_PIX_FMT_RGB32, V4L2_PIX_FMT_RGB555 >> and V4L2_PIX_FMT_RGB444 image formats. This patch adds a v4l2 control >> in order to let the applications control the alpha component value. >> >> The alpha value range depends on the pixel format, for RGB32 it's >> 0..255 (8-bits), for RGB555 - 0..1 (1-bit) and for RGB444 - 0..15 >> (4-bits). The v4l2 control range is always 0..255 and the alpha >> component data width is determined by currently set format on the >> V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE buffer queue. The applications >> need to match the alpha channel data width and the pixel format >> since the driver will ignore the alpha component bits that are not >> applicable to the configured pixel format. > > Will the driver ignore the least significant bits or the most significant > bits? Most significant bits will be ignored, i.e. depending on fourcc the valid alpha bits are: V4L2_PIX_FMT_RGB555 - [0] V4L2_PIX_FMT_RGB444 - [3:0] V4L2_PIX_FMT_RGB32 - [7:0] -- Regards, Sylwester -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
